This invention relates to the art of thread cutting and, more particularly, to an improved thread cutting die and method of making the same.
It is of course well known to provide threads on the end of a workpiece through relative rotational and axial displacement between the workpiece and thread cutting dies supported on a thread cutting die head. The die head may be manually rotated relative to the workpiece, or mounted on the tool carriage of a power driven threading machine in which the workpiece to be threaded rotates relative to the die head. Such a power-driven thread cutting machine is shown, for example, in U.S. Pat. No. 4,613,260 to Hayes, et al., the disclosure of which is hereby incorporated herein by reference for background information. The thread cutting dies are made from high speed steel bar stock and haste thread cutting teeth on one end thereof which extend in the direction of relative rotation between the die head and workpiece. It is known that the coating of such dies, including the teeth, with an ultra hard material such as titanium nitride having a hardness greater than that of high speed steels improves the cutting performance of the dies and extends the life thereof, especially in high volume output situations and in threading hard to cut materials such as stainless steel.